Baked Texture is Darker and uglier than the render
I think you did it right, but rendering is not the same as the viewport material preview. If your baking and your textures are large enough (not to loose detail because of that) increase the sample rate. Baking will take a while then too (maybe a hour or longer). Try a sample rate first double current then try 400 or 1000 

PS perhaps you should take a look what 2.8 eevee can do for your kind of work.